Fabrics having an ability to provide heat or warmth have been disclosed. For example, U.S. Published Application No. 2005/0061802 to Rock, discloses a fabric article that generates heat upon application of electrical power. In Rock, an electrical resistance heating element in the form of a conductive yarn is incorporated into a fabric prebody by a knitting or weaving process. The resulting fabric body incorporates the conductive yarn directly into its woven or knitted structure.
PCT publication WO 2003/087451A2 to Vikram Sharma (“Sharma”) discloses a tubular knit fabric system comprising an electrically insulating yarn, a stretch yarn, and a “functional” yarn knitted together to form a tubular knit fabric. In Sharma, the functional yarn is electrically conductive, having a resistance of 0.01 ohm/meter to 5000 ohm/meter. The functional yarn is embedded within the tubular knit in a continuous spiral that extends the length of a sleeve formed from the tubular knit. Body portions, such as limbs, are surrounded by a portion of the tubular fabric to measure physiological signs. In addition, these tubular knit fabrics disclosed by Sharma are adaptable for use in a narrow elastic band configuration in which the functional yarns serve as parallel conductors for electrical signals. A disadvantage of Sharms's narrow elastic band structures is that the functional yarns or wires must be knitted simultaneously into the structure with all other components.
The above references incorporate heating elements, such as electrical conductors or resistors, through the use of fabric structures of a woven or knitted type. Such elements can have poor compatibility with conventional textiles. Moreover, such elements generally cause difficulties in conventional fabric forming processes (e.g. weaving, knitting, seamless knitting). For example, wires and small cables often match poorly with typical textile fibers because of their fragility, elastic modulus, extensibility, and tensile strength. In particular, such disadvantages are notable where elastic recovery and flexibility from the structure or garment is desired and where the ability to wash or launder a garment is desired. Thus, flexible textile structures are needed that can overcome one or more deficiencies of the prior art.
The art continues to seek structures with elements able to provide heat or warmth, wherein the structures do not have at least one of the deficiencies mentioned above. An ability to launder fabric structures with heating elements in the same manner as regular garments are laundered would be highly desirable.